<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>3-JSONP</title>
</head>
<body>
  <script>
    // 前台
      let script = document.createElement('script');
      script.src = 'http://localhost:8081/jsonp-server?callback=fn';
      document.body.appendChild(script);

      function fn(data) {
        console.log(data);
        alert(data)
      }
  </script>
</body>
</html>